As I understand the expectation hypothesis says that the implied forward rate, can be used to predict future spot rates?
If $r_{0,2}$ is the rate for a zero coupon bond maturing in two years, and the same with $r_{0,1}$. And $r_{1,2}$ is the rate fora zero coupon bond sold at time $1$ and maturing at time $2$. Do we then have
$$1+2r_{0,2}=(1+r_{0,1})(1+r_{1,2})?$$
And by taking expectation we have $$E[r_{1,2}]=\frac{1+2r_{0,2}}{1+r_{0,1}}-1?$$
From what I understand there are 3 possible ways to take the expectation, it is under the real world measure, the risk neutral measure or the forward measure. Which is used?
What exaxtly does the expectation hypothesis mean?